


A Dragon In Heat

by Anonymous



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: F/M, FE3H Kinkmeme, Fluff and Smut, Mating Cycles/In Heat, Oral Sex, Plot What Plot/Porn Without Plot, Post-Timeskip | War Phase (Fire Emblem: Three Houses), Scent Kink, Vaginal Sex
Language: English
Status: Completed
Published: 2020-06-22
Updated: 2020-06-22
Packaged: 2021-03-04 00:14:59
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,874
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24864397
Author URL: https://archiveofourown.org/
Summary: Seteth goes into heat and Byleth is willing to help him out.
Relationships: My Unit | Byleth/Seteth
Kudos: 107
Collections: Anonymous





	A Dragon In Heat

**Author's Note:**

> Prompt:   
> https://3houseskinkmeme.dreamwidth.org/1608.html?thread=1868872#cmt1868872
> 
> Can I just... Get some partially transformed Seteth going absolutely feral on F!Byleth because his... "Instinct" is kicking in... he hasn't gotten any in god knows how long and it's doing things to his body now that he found someone he likes, so Byleth notices and is happy to assist. Slit pupils and fangs and enhanced sense of smell and whatnot... I am but a simple dilf loving scalie with a need.  
> +Post TS, route doesn't matter  
> ++He doesn't necessarily need to go FULL dom on her but rough enough that she's all "holy shit, did not expect this from a man of the cloth"  
> +++also some fluff would be nice adfhdfjhg

Seteth sucked in a deep breath as he leaned against the wall, half hunched over. His heart pounded uncomfortably in his chest, sweat dripping down his back and he feel his fangs poking out of his lower jaw. This was bad, really bad. It had been a long time since he had this sort of feeling and it had been a long time since he had to try to control it.

His vision was stronger than it usually was, his sense of smell heightened. _Her_ scent was everywhere in his room. Her sweet scent that reminded him of wildflowers and the wild.

He groaned as another wave of heat pulsed through him and he collapsed to his knees, his shaking legs unable to keep himself up anymore.

“Seteth!?”

Seteth shut his eyes and took a shaky breath, not believing in the ridiculous amount of luck that the person he didn’t want to show up would be the one to show up at this moment. Byleth kneeled in front of him, her scent wafting around him, invading his nose. Concern lit up her eyes but he could barely think straight from her cloying scent.

“Seteth, what’s wrong? Your eyes…”

He knew she was noting everything off about him, that was one of things he loved about her, her power of observation. She probably saw how his eyes were now slits, his trimmed nails longer than usual, the fangs poking out of his jaw and, much to his embarrassment, how his pants tented in the front.

Her eyes shifted back up to his face. “Seteth…”

He swallowed but it did nothing to curve the fire burning in him. His back itched and he knew his wings were starting to form, his tail starting to grow out of his tailbone. If he didn’t strip soon, the clothes he was wearing was going to be ruined.

“Seteth, what’s happening to you?” She put her hands on either side of his face but he pushed her away, the areas she touched on fire.

“Please Byleth, it is best if you, ah, leave me be for now.” He struggled to suck in another deep breath but it just made her scent wrap around him more, sending another wave of heat through him. “You cannot stay here…when I am like this. I…I do not want to do something I am going to regret.” He dug his nails into his palms, the pain helping his mind return to him somewhat. “It’s, ah, what is the word…” Even with the pain, his mind was not functioning at full strength, the word not coming to him. “Like when animals go into heat…” That was the only thing he could think of but even that thought fled as Byleth got closer and put her arms around him, his head buried in her shoulder. It took everything in his willpower to not put his arms around her, his nails digging into her back. Her scent was everywhere, invading every inch of him, his wings pushing against the fabric, his tail threatening to rip a hole in his pants.

“I am willing to do it with you if it will help you Seteth.”

“Byleth…I don’t think I will be kind to you if I do so…” Seteth had planned their first time to be sweet and gentle, perhaps under the starlight, not like this.

Byleth pressed a chaste kiss on top of his head and Seteth couldn’t help but groan as it pulsed through him all the way down to his crotch. “It’ll be fine Seteth. I can handle it and you know it.”

He wanted to protest further, to not give into the temptation flooding through him. However at the moment he was struggling to fight the urge to sing his teeth into her shoulder, marking her as his. “Alright,” he whispered. “Normally I wouldn’t ask this of you but please take your clothes off…I fear I might rip into them and destroy them otherwise…”

“Alright.”

Byleth pulled away and Seteth had to fight the urge to grab her and pull her in for a kiss. Instead he forced himself to look away from her, his enhanced hearing meant he could hear every scrap of fabric she took off. He took another shuddering breath, her scent surrounding him again, before he began the process of removing his own clothing. He stretched his wings as he freed them, barely the length of his arms. They were not strong enough to carry him while he was in human form. His tail was at its full length in his partial dragon form as well, almost as long as he was tall, the scales glittering in the candle light.

He heard Byleth gasp and he looked to her, blood rushing immediately to his cock. She was beautiful, her breasts perky, the mint green curly pubic hair hiding her sex.

“The wings…tail,” she said, her wide eyes looking at him.

“Another side effect,” he said hoarsely, moving towards her like a drunk man. He shook his head. “Will it be a problem?”

“Not at all. Just surprised…that’s all.”

The rest of her words were muffled as Seteth kissed her. He kissed her with passion, with everything he had been wanting to do for so long but held back. May it be for they were in the middle of a war or he was frightened he would scare her away, none of that mattered now.

He opened his eyes, checking where they were in the room before he pushed Byleth backwards onto his bed. Of course he gave her barely a chance to breathe before he climbed on top of her and passionately kissed her again, his tail wrapping around one of her thighs.

“Seteth,” she whispered as he pulled his lips from her and went to kiss her neck. His fangs poked slightly into the skin, not enough to draw blood but enough to claim her as his. She reached for him, her hands digging into his hair and he let her do so, the touch sending warmth and fire through him as he began moving downwards, leaving a trail in his wake. Bite marks to mark her as his. Her shoulders, her collar bone, they were all his. He shifted the position of his tail, wrapping it around her other thigh, tight enough that it would probably bruise. His.

He reached her breasts and touched them with his fingers, careful to not draw blood from his sharper fingernails. First he examined them with his hands, massaging them with his fingers, pinching her nipples. He loved how her back arched, the moans of his name rolling off her tongue. He gently put his mouth on one of her nipples, his fangs poking slightly into the skin as he explored her nipple with his tongue.

Her hands dug into his hair and he could feel her moving her legs through his tail around her thigh. He pulled away from her breast, his tail loosening from around her thigh and heard her groan in protest.

A small smile crossed his face as he shifted downwards, continuing to claim her with bites. She trembled as he reached the apex of her thighs and he looked up at her. He may be in heat but he wanted her to find this pleasurable as well.

Byleth looked down at him with half glazed eyes and noticing he was looking at her, she smiled. “I’m alright,” she whispered.

That was all he needed.

He lowered his head, his tongue slightly longer now due to the half dragon transformation and he put it to good use, claiming her sex as his. Byleth’s moans echoed in his ears, her scent surrounding him as he explored her with his tongue. Her taste was similar to her scent and it just pushed him further, trying to find every little bit of her.

He could feel his cock throbbing, the need starting to overtake everything else in him. He couldn’t wait any longer. He pulled away from her sex, so wet now that she was starting to soak into his sheets. “Turn over. On your knees,” he growled, the dragon in him too powerful at the moment.

Byleth’s eyes widen slightly through her hazy vision but she complied, turning over and pulled herself up ono her knees, her head against the sheets. “Please Seteth,” she whispered. Her whisper turned into a gasp as he pushed himself into her.

He grunted as he did so, she was tighter than he thought she would be and in the back of his mind he knew it was because the dragon blood made his cock bigger than it usually was. He wanted to thrust but he forced himself not to, to let Byleth get used to the feel of him inside of her. “You okay?” he growled, still fighting the urge to claim her right then and there.

He could feel her shuddering and shifting positions slightly. “Yes. Go on. I’m fine. Ah…” Seteth had full control of his tail and he shifted it forward so it wrapped around her breasts, her nipples pressed against the soft underside of it.

Then he began thrusting.

Furious thrusts, wild thrusts, he poured all of the feelings he had for her into it. “You’re mine, all mine.”

Byleth responded with cries of his name, her hands gripping the sheets tightly as he showered her with all of the love he had for her. She was the first to hit her peak, her walls gripping him tightly as Seteth pushed through it, chasing his own. 

With a shudder, he expelled into her, instinctively keeping a tight grip on her until he felt his release subside.

Breathing heavily, he pulled out and released her from the grip of his tail. Byleth collapsed on her side, obviously unable to keep herself up with her own strength. Seteth laid down next to her, one arm protectively around her waist, his tail around her knees as he examined her face for any signs of pain. He was still in the midst of his own heat but it was tempered somewhat for now since he was able to fill his need.

“Byleth, are you alright?” He gently pushed a few strands of hair out of her face.

Byleth looked up at him and gave him a soft smile. “I wasn’t expecting something like that from you.”

“What…what do you mean by that?”

“I mean you being rougher than I was expecting. It was good though Seteth, I like this part of you.”

He cleared his throat and looked away, not sure how to take her declaration. “I am happy I did not hurt you. I was doing my best to keep the urges in check.”

She gave him a soft kiss on the lips. “Well maybe you should give into those urges a little more next time then.” She reached down and gently ran her fingers along his cock and he sprang up from her attention.

Seteth shuddered, the heat pulsing through him again at full force. “If you say so Byleth, this time I will not hold back at all.”

Byleth smiled. “I’m looking forward to it.”


End file.
